(57) Olefin polymers which are unsuited, or ill-suited, for heating, seating, or bonding by the action of high-frequency electromagnetic radiation, especially microwave radiation, are rendered heatable by such radiation by incorporating carbon monoxide, as a comonomer, into the polymer structure. Novel adhesives comprising terpolymers of ethylene/carbon monoxide/acids are disclosed, where the acid moiety of the terpolymer is at least one carboxylic acid polymerizable through carbon-to-carbon unsaturation, and salts thereof.